Sciencemadness Discussion Board

Drying Molecular Sieve in a Microwave Oven

jpsmith123 - 27-12-2007 at 17:24

I'm wondering, has anyone ever tried to dry any flavor of zeolite in a microwave, and if so how well did it work?

Reference Information

solo - 27-12-2007 at 18:18

The microwave technique: A new route for high dispersion of inorganic salts onto supports
F. -S. Xiao1, W. Xu1, S. Qiu1 and R. Xu
Journal of Materials Science Letters Volume 14, Number 8, page 598-599, January, 1995


Excerpt
.........In comparison with other methods such as ionexchange, impregnation and monolayer dispersion, the dispersion of inorganic salts onto the surface of supports by the microwave method exhibits the following features: (i) high loadings of inorganic salts may be dispersed onto the surface of supports;
(ii) microwave treatment time is very short; generally, treatment of 10 min can achieve high dispersion; (iii) the sample preparation is very simple, avoiding stirring of solution, drying and calcination; and (iv) inorganic salts can easily be dispersed in porous solids not having ion-exchange capacity, such as silicalite-I zeolite.

Attachment: The microwave technique-A new route for high dispersion of inorganic salts onto supports.pdf (236kB)
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jpsmith123 - 27-12-2007 at 19:06

Hi Solo,

Thanks for the interesting paper. Although it's not primarily concerned with drying, it mentions a drying effect, and doesn't mention any incompatabilities.

When my material arrives I guess I'll give it a try.

physics of drying zeolites w/MW

chemrox - 27-12-2007 at 20:08

This paper may have useful information as well.

Attachment: MW-dehyd-zeos.pdf (578kB)
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MilordB - 30-11-2009 at 07:16

I have done it many times but you should pay attention as it heats up to 400-600°C easily. So put the zeolite in the microwave for a couple of minuts and the stire. and add a couple more minutes untill you reach the desired temperature. you see it is classic chemistry stirring and heating.
It always works.

Milord B

Texium - 30-9-2016 at 12:03

Does anyone here have practical experience using a microwave oven to dry molecular sieves? If so, what is you usual procedure for doing so? There seems to be little practical information (e.g. how long to leave them in the microwave to reach acceptable dryness) available. The papers posted in this thread are interesting, but of little help from a practical standpoint.

[Edited on 9-30-2016 by zts16]

zed - 30-9-2016 at 12:31

Sound like a good idea, but I would attempt to do it while applying vacuum. Get that water out of there.

Not unlike, the procedures recommended to dehydrate Phosphoric acid to PolyPhosphoric acid.

aga - 30-9-2016 at 14:28

The question is easily answered by the OP conducting a few very simple experiments.

The results of the OP's experiments will/would be interesting.

As per usual, there probably will be no follow-up, no experiments, no photos, no write-up, no data, no Effort of any interest at all.

I'll give it until christmas before declaring it 'YAPOS' (acronym).

Cryolite. - 30-9-2016 at 21:04

I guess I can provide my experience...

Using borosilicate glass when drying sieves is an absolute MUST. Sieves can easily reach a dull red heat in the microwave, and pretty much anything short of borosilicate will crack under the immense thermal stress. In addition, it is important to only place one or two layers of sieves in the microwave at a time: any more will lead to increased heating times, and since sieves don't conduct heat well, a higher risk of cracked glassware results.

Other than that, a procedure which has worked for me in the past is to microwave for 45-60 seconds on HIGH in a small evaporation dish(1 kW microwave), allow the sieves to cool, and continue to microwave in 30-40 second increments until no more water condenses on the side of the evaporation dish. Then, microwave for 30 seconds twice more, with a cooling break in the middle. Typically, this equates to 6 or 7 cycles in total to dry about 25 grams of sieves. This works very well to produce sieves for drying ethanol.

However, if you prefer a "set and forget" procedure, I don't think anything can beat placing sieves in a small oven set to above 250 C for a couple hours.

[Edited on 1-10-2016 by Cryolite.]

[Edited on 1-10-2016 by Cryolite.]

j_sum1 - 1-10-2016 at 04:59

Quote: Originally posted by aga  
The question is easily answered by the OP conducting a few very simple experiments.

The results of the OP's experiments will/would be interesting.

As per usual, there probably will be no follow-up, no experiments, no photos, no write-up, no data, no Effort of any interest at all.

I'll give it until christmas before declaring it 'YAPOS' (acronym).

I think you are being a bit harsh here aga.
The question was a good one and not something I had thought of. zts evidently did a search and found this old and not totally useful thread. It was worthwhile asking for recent experience before attempting it -- especially since he is sans-lab at the moment.


I have some 3A sieves that I have not had occasion to use at this point. I think when I do, I wil try the microwave method -- if only because I will have a microwave in my lab but not an oven that reaches that temperature. I think I'll make a drawstring bag out of a fire blanket and suspend it on some kind of frame. That way I won't risk busting anything expensive.